Ultra wideband communication link

Ultra-wideband communication (UWB) has been a topic of extensive research in recent years especially for its short-range communication and indoor applications. The preliminary objective of the project was to develop a description and understanding of the basic components of the communication link at microwave frequencies in order to achieve the primary objective of establishing a communication setup at a bandwidth of 2.5 GHz for testing Ultra Wideband (UWB) antennas. This was achieved with the aid of commercially available optical system which was modified for the purpose. Beginning with the generation of baseband narrow pulses with energy spanning over a broad frequency range, through multiplexing of different parallel channels carrying these pulses into a single stream, to finally capturing the received signal to understand the effect of the communication link formed; all provided basis for identifying the issues and possible solutions to establishing a reliable communication link at UWB frequency

MAC layer implementation of the IEEE 802.15.3c standard

The transfer of data without wires is one of the main handicaps on this time. Not only for commercial reasons, also for research and manufacturing. The wireless technology on multimedia streaming has to evolve as fast as the multimedia technology does. Multimedia technology is evolving in order to reach better quality for the user's screen, therefore it needs more capabilities requirements; as better screens, better encoders, better devices to reproduce them. If we add the multimedia and the wireless technology, the result is that we need a wireless channel which could support the bandwidth that the video encoder needs. The uncompressed video or High Definition multimedia has entered so fast on the commercial issues. The main problem with that is the large amount of disk space that it needs, therefore the high rate transmission that require for streaming. To stand up to this with the wireless technology, the IEEE has developed the standard 802.15.3c in order to reach the data rate needed to transport the multimedia data without need wires. This standard is based on personal area networks (WPAN), which are computer networks used for communications between computer devices; including telephones, smartphones and tablets. Typically, a wireless personal area network uses some technology that permits communication within about 10 meters - in other words, a very short range. One such technology is Bluetooth. The WPANs could serve to interconnect all the ordinary computing and communicating devices that many people have on their desk or carry with them today. It is in its infancy and is undergoing rapid development. Proposed operating frequencies are around 2.4 GHz in digital modes. This standard uses the extremely high frequency of 60 GHz, it is considered between the highest radio frequency bands, from 30 to 300 GHz above which electromagnetic radiation is considered to be low (or far) infrared light. On this frequency band the rates could be greater than 5 Gbps, against the 2.5 Gbps that the uncompressed 1080p video, it is a good solution. The 60 GHz band usually requires line of sight between transmitter and receiver, and the 802.15.3c standard specification ameliorates this limitation through the use of "beam forming" at the receiver and transmitter antennas to increase the signal's effective radiated power. iii The aim of this bachelor thesis is to build a simulator of the 802.15.3c MAC layer protocol, in order to study the ways of the standard to construct a piconet, the structure of the channel time and the different modes to transmit data that is implemented on it. First of all, there is a summary of the main process of the standard to reach communication between two devices and an explanation of the MAC frames used for it. After that, I am going to talk about how is working the simulator and the results of it. Finally, the document is finished with conclusions and future works on the simulato

SPACE-TIME BEHAVIOR OF MILLIMETER WAVE CHANNEL AND DIRECTIONAL MEDIUM ACCESS CONTROL

An appropriate channel model is required to evaluate the performance of different physical (PHY) layer designs. However, there is no known space-time millimeter wave channel model that could benefit the use of directional antennas that is applicable in environments with lots of reflections such as residential or office. The millimeter wave signal strength is subject to temporal and spatial variations. The focus of the first part is the investigation of the characteristics of the millimeter wave propagation model. By analyzing measurement data of millimeter wave channels for indoor environments, space-time clusters are identified, and intercluster statistics for millimeter wave propagation are calculated. Correlation of the identified space-time clusters to the propagation environment is determined. In the second part, the effectiveness of the ray-tracing method in creating channel realizations in the intercluster and intracluster levels for millimeter wave indoor environments is validated. In the third part, a protocol to establish an optimal directional link between two nodes equipped with directional antennas is presented. The correctness of the protocol for different scenarios is illustrated using a ray-tracing tool. Then in the forth part, a Directional MAC (D-MAC) for supporting millimeter wave technology exploiting directional antennas is presented. The D-MAC is compatible with the current IEEE 802.15 MAC of WPAN, and it has backward compatibility to support devices which are not equipped with directional antennas. Finally, a directional neighbor discovery algorithm is presented which does not require time synchronization or any location information of communicating nodes. This means two nodes equipped with directional antennas can discover and communicate with each other through an established directional link as part of the D-MAC

About the Use of Adaptive Antennas in 60 GHz UWB-OFDM Personal Area Network Transceivers

The recent opening of unlicensed spectrum around 60 GHz has raised the interest in designing gigabit Wireless Personal Area Networks (WPANs). Since at 60 GHz the signal attenuation is strong, this band is basically suitable for short range wireless communications. It is understood that directional antennas can be employed to compensate for the path loss and combat the waste of power due to the scatter phenomena characteristic of these high frequencies. This thesis studies the use of adaptive array systems in 60 GHz Ultra Wide Band-Orthogonal Frequency Division Multiplexing (UWB-OFDM) personal area network transceivers. The study has been conducted by simulations and theoretical analysis. Two sensor arrangements have been considered, the Uniform Linear Arrays (ULA) and the Uniform Circular Arrays (UCA), in the simple case of the Line of Sight (LOS) transmission scenario. On the one hand we have designed a IEEE 802.15.3c Medium Access Control (MAC) phased-array controller throughput using Direction of Arrival (DOA) estimation to perform beamsteering. We have simulated the MAC controller with the network simulator ns-2. The impact of the array controller performance onto the achievable throughput of the wireless links has been studied to draw the requirements about the standard deviation of the DOA estimator. On the other hand, we have found the Cramér-Rao Bound (CRB) for DOA estimation of impinging 60 GHz OFDM sources. The requirements of the standard deviation of the DOA estimator are analysed against the CRB for DOA to validate the design of the directional 60 GHz UWB-OFDM transceivers. The comparison reveals that directional 60 GHz UWB-OFDM transceivers can achieve high wireless throughput with a number of pilot subcarriers and for a Signal to Noise Ratio (SNR) operating range typical of next generation WPAN